Syringe for local anaesthesia



Jan. 18, 1927.

J. L. RAISON sumas yF011 L ocAL ANmsTgEsIA Filed Feb. 5 1923 JL Eluvenr 015077/ llwmmqlall #Mr/myst' Patented Jan.. 18, 1927.

PATENT OFFICE.

JEAN LOUIS RAISON, OF PARIS, FRANCE.

SYRINGE FOR LOCAL ANIESTI-IESIA.

Application led February 5, 1923, Serial `No. 617,140, and in France February 17, 1922.

The present invention relates to a syringe for local anaesthesia, used in surgery and more particularly in dentistry.

This apparatus is designed in a special manner so as to present the following advantages:

To enable assembling and disassembling to be rapidly effected without the use of any wrench or any similar tool;

To insure perfect tightness while, at the same time,'avoiding the drawback that the joint situated at the base of the needle, and consisting of a .soft metal, may either obstruct the channel thereof or jam the device for securing the needle on the syringe;

By means of a joint made of felt, surrounding the piston, to enable the syringe to be sterilized by boiling without the risk of interfering with the operation of the instrument.

The invention is shown diagrammatically and by way of example in the accompanying drawing in which:

Fig. 1 is an axial longitudinal section of the syringe.

Fig. 2 is a section along A-B seen from below in Fig. 1 and Fig. 3 is a section along A-B seen from above in Fig. 1.

The syringe consists essentially of a pumpbody 1 which terminates at one end in a reduced portion 2 having a hole bored axially therein; the' other extremity is provided. with a screw thread 3. A nut is screwed upon the threads 3 and this nut, which is hollow, contains a tight packing 5 made of felt, which ensures the formation of a tight joint. A piston 6 slides in the body of the pump 1. A needle-holder or nipple 7 having the form shown is fixed to the end of the pump by a nut 8 screwed upon the thread 9 of the body of the pump and guided by this latter.

The piston 6 is constituted by a rod 16 upon which are fixed a handle 11 and a member 12 provided with two pins 13.

The nut 4 carries two lugs 14 with which the pins 13 can engage. By this arrangement and as shown in Figs. 1 and 3, the nut 4 can be screwed on the body of the pump by operating the handle 11, since the projections of this handle take with them the lugs 14 of the nut 4. The method of effecting entrainment of the nut by the handle could, however, be different from that just described.

The nut 8 carries either two studs terminating in knobs 10 as shown in Fig. 1, or a knurled portion, or again any system which enables it to be screwed by hand without the use of any wrench or similar tool, thereby rendering its manipulation easy and rapid.

The needle-holder 7 is provided interiorly with a cylindrical portion terminated by a concave cone 15 at the top of which opens a narrow channel of substantially the same external diameter as the needle. The needle has at its base a soft metal head which, when the nut 8 is clamped upon the body of the pump 1, is crushed and fills up the conical portion of the needle-holder 7. Tightness is therefore ensured in a perfect manner, owing to the conical portion 15 and furthermore the channel of the needle cannot be obstructed, this latter being engaged, to a slight extent, in the bore of the reduced portion 2. Furthermore, owing` to the fact that the needle-holder is assembled with the body of the pump by means of a Aspecial nut rather than by screwing` directly on the body of the pump the threads are out of Contact with the soft metal, which permits of jamming of the two parts being avoided.

I claim:

1. A syringe comprising an elongated pump-body having a reduced projecting hollow end and having external threads approximately midway of the length of the body, a piston slidable in said pump-body, a nipple having an enlarged upper portion to fit snugly about the reduced projecting end of said pump-body and providing an enlarged Ispace outwardly of said projecting part of the pump-body, said nipple having an outer reduced hollow neck, said enlarged portion ofthe nipple having a fiange extending outwardly therefrom, and an elongated sleeve nut having a similar flange to engage about said flange of the nipple, said sleeve nut fitting about said pump-body, and having threads for engaging with the threads on the intermediate portion of the pumpbody.

2. A syringe comprising an elongated pump-body having a reduced projecting and hollow end portion, a plunger in said pumpbody, a nipple having a flange at its inner end and an enlarged concave space for {itting about the projecting portion of the pump-body, said Space extending, outwardly beyondv said reduced portion, a flanged elongated sleeve nut fitting about said nipple and engaging the ange thereof, .said sleeve nut being secured to the pump-body at a 1remote point from said nipple, said nipple having a reduced hollow outer end, a needle 10 engaging through said hollow reduced end of the nipple,v and a head of soft material on the needle adapted to be crushed in said concave enlarged space of the nipple when the sleeve is tightened on the cylinder.

JEAN LOUIS RAISON. 

